MDEV-26450: Corruption due to innodb_undo_log_truncatebb-10.2-MDEV-26450

At least since commit 055a3334adc004bd3a897990c2f93178e6bb5f90
(MDEV-13564) the undo log truncation in InnoDB did not work correctly.

The main issue is that during the execution of
trx_purge_truncate_history() some pages of the newly truncated
undo tablespace could be discarded.

fsp_try_extend_data_file(): Apply the peculiar rounding of
fil_space_t::size_in_header only to the system tablespace,
whose size can be expressed in megabytes in a configuration parameter.
Other files may freely grow by a number of pages.

fseg_alloc_free_page_low(): Do allow the extension of undo tablespaces,
and mention the file name in the error message.

mtr_t::commit_shrink(): Implement crash-safe shrinking of a tablespace
file. First, durably write the log, then shrink the file, and finally
release the page latches of the rebuilt tablespace. Refactored from
trx_purge_truncate_history().

log_write_and_flush_prepare(), log_write_and_flush(): New functions
to durably write log during mtr_t::commit_shrink().

2 files changed, 5 insertions, 81 deletions

diff --git a/mysql-test/suite/innodb/r/undo_truncate.result b/mysql-test/suite/innodb/r/undo_truncate.result
index 89171d36d0f..67a587b3c1c 100644
--- a/mysql-test/suite/innodb/r/undo_truncate.result
+++ b/mysql-test/suite/innodb/r/undo_truncate.result
@@ -10,28 +10,12 @@ SET @trunc_start=
 WHERE variable_name = 'innodb_undo_truncations');
 create table t1(keyc int primary key, c char(100)) engine = innodb;
 create table t2(keyc int primary key, c char(100)) engine = innodb;
-CREATE PROCEDURE populate_t1()
-BEGIN
-DECLARE i INT DEFAULT 1;
-while (i <= 20000) DO
-insert into t1 values (i, 'a');
-SET i = i + 1;
-END WHILE;
-END |
-CREATE PROCEDURE populate_t2()
-BEGIN
-DECLARE i INT DEFAULT 1;
-while (i <= 20000) DO
-insert into t2 values (i, 'a');
-SET i = i + 1;
-END WHILE;
-END |
 connect  con1,localhost,root,,;
 begin;
-call populate_t1();
+insert into t1 select seq,'a' from seq_1_to_20000;
 connect  con2,localhost,root,,;
 begin;
-call populate_t2();
+insert into t2 select seq,'a' from seq_1_to_20000;
 connection con1;
 update t1 set c = 'mysql';
 connection con2;
@@ -53,8 +37,6 @@ commit;
 disconnect con2;
 connection default;
 drop table t1, t2;
-drop PROCEDURE populate_t1;
-drop PROCEDURE populate_t2;
 InnoDB		0 transactions not purged
 SET GLOBAL innodb_undo_logs = @save_undo_logs;
 SET GLOBAL innodb_purge_rseg_truncate_frequency = @save_frequency;
diff --git a/mysql-test/suite/innodb/t/undo_truncate.test b/mysql-test/suite/innodb/t/undo_truncate.test
index 4f350e380ee..9feee84491a 100644
--- a/mysql-test/suite/innodb/t/undo_truncate.test
+++ b/mysql-test/suite/innodb/t/undo_truncate.test
@@ -5,6 +5,7 @@
 # --source include/innodb_page_size.inc
 --source include/innodb_page_size_small.inc
 --source include/have_undo_tablespaces.inc
+--source include/have_sequence.inc
 
 call mtr.add_suppression("InnoDB: The transaction log size is too large");
 
@@ -27,37 +28,14 @@ WHERE variable_name = 'innodb_undo_truncations');
 create table t1(keyc int primary key, c char(100)) engine = innodb;
 create table t2(keyc int primary key, c char(100)) engine = innodb;
 #
-delimiter |;
-CREATE PROCEDURE populate_t1()
-BEGIN
-        DECLARE i INT DEFAULT 1;
-        while (i <= 20000) DO
-                insert into t1 values (i, 'a');
-                SET i = i + 1;
-        END WHILE;
-END |
-delimiter ;|
-#
-delimiter |;
-CREATE PROCEDURE populate_t2()
-BEGIN
-        DECLARE i INT DEFAULT 1;
-        while (i <= 20000) DO
-                insert into t2 values (i, 'a');
-                SET i = i + 1;
-        END WHILE;
-END |
-delimiter ;|
-#
-#
 let DATADIR = `select @@datadir`;
 connect (con1,localhost,root,,);
 begin;
-send call populate_t1();
+send insert into t1 select seq,'a' from seq_1_to_20000;
 
 connect (con2,localhost,root,,);
 begin;
-send call populate_t2();
+send insert into t2 select seq,'a' from seq_1_to_20000;
 
 connection con1; reap; send update t1 set c = 'mysql';
 connection con2; reap; send update t2 set c = 'mysql';
@@ -67,25 +45,12 @@ connection con1; reap; send delete from t1;
 connection con2; reap; delete from t2;
 connection con1; reap;
 
-let CHECKFILE = $MYSQL_TMP_DIR/check.txt;
-perl;
-($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size1)
-	= stat("$ENV{DATADIR}/undo001");
-($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size2)
-	= stat("$ENV{DATADIR}/undo002");
-open(OUT, ">$ENV{CHECKFILE}") || die;
-print OUT "let \$size1='$size1,$size2';\n";
-close(OUT);
-EOF
-
 SET GLOBAL innodb_undo_log_truncate = 1;
 commit; disconnect con1;
 connection con2; commit; disconnect con2;
 
 connection default;
 drop table t1, t2;
-drop PROCEDURE populate_t1;
-drop PROCEDURE populate_t2;
 
 --source include/wait_all_purged.inc
 
@@ -100,29 +65,6 @@ if (`select @@innodb_page_size IN (4096,8192,16384)`)
   source include/wait_condition.inc;
 }
 
---source $CHECKFILE
-perl;
-($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size1)
-	= stat("$ENV{DATADIR}/undo001");
-($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size2)
-	= stat("$ENV{DATADIR}/undo002");
-open(OUT, ">$ENV{CHECKFILE}") || die;
-print OUT "let \$size2='$size1,$size2';\n";
-close(OUT);
-EOF
-
---source $CHECKFILE
---remove_file $CHECKFILE
-
-if ($size1 == $size2)
-{
-  # This fails for innodb_page_size=64k, occasionally also for 32k.
-  if (`select @@innodb_page_size IN (4096,8192,16384)`)
-  {
-    echo Truncation did not happen: $size1;
-  }
-}
-
 SET GLOBAL innodb_undo_logs = @save_undo_logs;
 SET GLOBAL innodb_purge_rseg_truncate_frequency = @save_frequency;
 SET GLOBAL innodb_undo_log_truncate = @save_truncate;